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c. 1870'S


Zentmeyer Condenser

Zentmeyer Condenser

Zentmeyer Condenser

reference for zent diaphzent diaph DESCRIPTION:

This rare condenser features an ingenious mechanism to regulate the substage aperture of light. This mechanism, invented by Joseph Zentmeyer is well described in the accompanying original description shown to the left. It has an RMS standard diameter condenser housing of about 38.5 mm. This example also features a wheel of three blue glass discs (diam=14 mm) of varying density, as well as one empty circle. The condenser housing accepts any RMS thread objective for its optics. It is shown here with a Beck 1/4 inch, but any suitable objective could be used. It still functions perfectly, though one of the glass discs has a crack in it. The lacquer is in very good condition with minimal losses.


This instrument was invented by Joseph Zentmeyer the famous microscope maker and inventor of the type of swinging substage with its axis at the level of the stage. Like Zentmayer's swinging substage, this instrument was likely copied by the English makers. James Swift frequently included tinted blue glass discs in his condensers and so it is feasible that this example is by Swift. This condenser is much simpler to manufacture than one with an iris diaphragm and therefore would have been much less expensive; nevertheless, it never really caught on and is a rarity today.